Push-button tuner

ABSTRACT

Disclosed is a push-button tuner having a plurality of push-buttons which are preset so as to tune in to preset frequencies of broadcasting stations, in which an actuator plate for setting the positions of variable tuning elements by depressing the push-buttons is divided into a plurality of actuator plate components and the variable tuning elements are allotted to the actuator plate components, the push-buttons being grouped corresponding to the actuator plate components, thereby reducing the actuator plate in size as well as in weight so that it is possible to tune in to the frequency of a desired broadcasting station with a light pressing force.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to push-button tuners for radioreceivers and more particularly to a push-button tuner in which twopreset broadcasting frequencies can be desiredly selectively tuned in byeach push-button.

2. Description of Prior Art

Widely known is a push-button tuner comprising a plurality ofpush-buttons each of which is set to tune in to a preset broadcastingfrequency so that a desired broadcasting frequency is tuned in bydepressing a selected one of the push-buttons into its actuatedposition. In such a push-button tuner, usually, only one broadcastingstation could be selected by one push-button so that in order to tune into several broadcasting stations by push-buttons it has been necessaryto provide several push-buttons corresponding to the number ofbroadcasting stations. To increase the number of push-buttons, however,it is necessary to enlarge, in the direction perpendicular to the axialdirection of a tuning shaft, the length of an actuator plate which movesas the tuning shaft moves to thereby define the position of a variabletuning element. In the case where the length of the actuator plate iselongated, however, there is a tendency for the actuator plate inclinein the direction of movement when a tuning shaft near each of oppositeends of a tuner is retracted. If the actuator plate inclines, there aredisadvantages that not only the smooth movement of the actuator plate ismade difficult but there is a possibility of causing an erroneous tuningoperation. In a push-botton tuner which is intended to be reduced insize, it is necessary to reduce the depth of the actuator plate andthere is a strong possibility that the actuator plates will incline.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a push-button tunerwhich has a capability of tuning in to several broadcasting stationswith an actuator plate having no tendency to incline.

In order to attain the object, according to the present invention, thepush-button tuner comprises a support, a tuning means mounted on thesupport in a manner so that the tuning means is movable to positionscorresponding to tuned frequencies for producing the tuned frequencies,and a plurality of presettable tuning mechanisms for adjusting thetuning means to move selectively to positions respectively correspondingto specific frequencies, in which each of the tuning mechanismscomprises: a rotatable operation member movable between a frontnon-actuation position and a rear actuation position, the operationmember being normally urged to the front non-actuation position, theoperation member having a drive rotary body and a push-button providedat an end of the operation member, the push-button being used also as arotating knob; a rotatable tuning member having a driven rotary body forselectively engaging with the drive rotary body to rotate together withthe drive rotary body, the rotatable tuning member being supported in amanner so that the rotatable tuning member is normally urged to thefront non-actuation position while it is movable between the frontnon-actuation position and the rear actuation position, the rotatabletuning member having a longitudinally extending threaded portion at apart of the surface thereof and a tuning piece engaged with the threadedportion, the tuning piece being movable in the frontward/rearwarddirection in response to the rotation of the tuning member; the tuningmeans including a plurality of actuator plates engaging with the tuningpiece of the tuning member in the rear actuation position to adjust thetuning means, each of the actuator plates cooperating with a presetnumber of the tuning mechanisms, each of the actuator plates beingprovided with a variable tuning element; and in which the push-buttontuner further comprises a lock member for holding any one of the tuningmembers so as to permit the transmission of rotation between the driverotary body and the driven rotary body when one tuning member is locatedin the rear actuation position and for releasing the tuning member heldin the rear actuation position when another tuning member is disposed inthe rear actuation position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view with parts omitted of a first embodiment of thepush-button tuner according to the present invention;

FIG. 2 is a longitudinal sectional view taken on line 2--2 in FIG. 1;

FIG. 3 is a longitudinal sectional view taken on line 3--3 in FIG. 1;

FIG. 4 is a perspective view showing in detail the guide member of FIG.5;

FIG. 5 is an exploded perspective view of the change-over mechanism ofFIG. 1;

FIG. 6 is a partial plan view showing the tuning mechanism of FIG. 1when in operation;

FIG. 7 is an internal view showing the relation between the upper plateand the actuator plate in the first embodiment;

FIG. 8 is a plan view with parts omitted showing a second embodimentaccording to the present invention;

FIG. 9 is a partly cut-away plan view of the tuning mechanism of FIG. 8;

FIG. 10 is a longitudinal sectional view taken on line 10--10 in FIG. 9;

FIG. 11 is a longitudinal sectional view taken on line 11--11 in FIG. 8;

FIG. 12 is a plan view showing the tuning mechanism of FIG. 8 when inoperation; and

FIG. 13 is a plan view showing the relationship between the supportplate and the lock plate.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, preferred embodiments of the presentinvention will now be described. The same element is designated by thesame reference numeral in the embodiments and the explanation as to thesame element as described in the preceding embodiment is omitted in thedescription of the succeeding embodiments.

Referring to FIGS. 1 to 7, a first embodiment of the present inventionwill be described. In this embodiment, ten broadcasting stations aretuned to by five sets of tuning mechanisms each having a push-button.Since each of the tuning mechanisms has the same construction, only oneof the tuning mechanisms is described and illustrated. The tuningmechanism is generally designated by reference numeral 11 and has acylindrical push-button 12 attached at its forward end, an operationshaft 13 attached to the push-button 12, and two tuning shafts 14 and 14are respectively arranged on opposite sides of shaft 13 that is itsright and and left sides, as seen in the drawing. In the followingdescription, the word "front" is used to designate the ene of shaft 13at which the push-button 12 is attached and the word "rear" is used todesignate the other end. The respective front and rear of the operationshaft 13 and the tuning shafts 14 and 14 are movably received andsupported by holes 18 formed in front-end and rear-end rising portion 16and 17 of a support plate 15.

A helical spring 19 for elastically displacing the operation shaft 13 tobias the operation shaft 13 normally toward member 16 is positioned onshaft 13 between push-button 12 and the front-end rising portion 16. Asupport member 23 having flanges 21 and 22 at its two ends is providedon the operation shaft 13 between the front-end and rear-end portions 16and 17 such that the operation shaft 13 passes through holes formes inthe flanges 21 and 22 so as to be supported by the support member 23.Support member 23 is maintained on the operation shaft 13 as by stops 40so that it is free to move in a rotary direction relatively to theoperation shaft 13 but is prevented from moving in an axial directionoperation shaft 13. When push-button 12 is released, the bent or flange21 of support member 23 is normally in contact with the rear surface offront-end rising portion 16 in order to restrict the outward movement ofoperation shaft 13 under the force of the spring 19. A pin 24 isprovided centrally in the rear surface of support member 23 and a pinion25 is rotatably mounted on pin 24. A portion 27 of operation shaft 13 isaxially partly cut away so as to make its cross-section non-circular anda drive gear 28 is fitted onto this non-circular portion such that it isfree to slide in the axial direction of operation shaft 13 while beingprevented from movement in the rotary direction. A helical spring 29 ismounted on the operation shaft 13 between drive gear 28 and the rear-endrising portion 17 so as to bias drive gear 28 toward the front at alltimes. The other surface of the drive gear 28 opposite the surface incontact with the helical spring 29 strikes an abutment 32 which is cutout and bent from a bottom plate 31 of the support plate 15 so as torestrict the movement of the drive gear 28 in an axial direction alongoperation shaft 13. Each of the two tuning shafts 14 and 14 whichcooperate with the operation shaft 13 has the same structure. Eachtuning shaft 14 supported to be rotatable and is slidably at its frontand rear ends by the front-end and rear-end rising portions or walls 16and 17 of support plate 15. A gear 36 having a diameter larger than thatof the drive gear 28 is mounted on each tuning shaft 14 rear its rearportion. A helical spring 38 is mounted on each tuning shaft 14 betweenthe driven gear 36 and rim 17 for biasing the tuning shaft 14 toward thefront at all times. A guide member 42 having bent portions 39 and 41 atits opposite ends is mounted on each tuning shaft 14 between anengagement/stopper portion 34 and the front-end rising portion or wall16 so that the portion of guide member 42 between its opposite bentportions 39 and 41 is perpendicular to the surface of the bottom plate31 of the support plate 15 and the guide member 42 is swingable isprevented from axial movement by an abutment 40. That is, the tuningshaft 14 loosely passes through through holes (not shown) formed in therespective bent portions 39 and 41. A threaded portion 43 is formed ontuning shaft 14 between the ends of guide member 42 and a tuning piece45 is engaged with the threaded portion 43, the tuning piece 45 havingan upwardly projecting memory protrusion 44 formed on its upper surface.As shown best in FIG. 4, the guide member 42 has, in addition to thebent end portions 39 and 41, a lower flange 46 which is parallel to withthe bottom plate 31 of support plate 15, and has a rack portion 47formed along its a longitudinal side edge which engages with pinion 25,and has a downwardly projecting portion 48, and a protrusion 49 isintegrally formed at a lower portion of bent portion 39. In bottom plate31 of support 15, there is a first elongated guide slot 51 which engageswith the front end of the engagement/stopper portion 34 for guiding theforward and rearward movement of the latter, and a second elongatedguide slot 52 which engages with the protrusion 49 of the guide member42 for guiding the frontward/rearward movement of the latter. Each ofthe first and second elongated slots 51 and 52 is located directly belowthe tuning shaft 14 and longitudinally extended in the axial directionof the tuning shaft 14.

A lock plate 53 is provided which is movable perpendicularly to theoperation shaft 13 on the rear portion of the bottom plate 31 of thesupport plate 15. Longitudinally elongated holes 54 are formed in thelongitudinally opposite ends of the lock plate 53, and pins 55respectively supported by the bottom plate 31 are fitted in theelongated holes 54 so as to restrain the amount of movement of the lockplate 53 in the left-right direction. One of a spring 56 is attached tothe bottom plate 31 and the outer end is attached to the lock plate 53so as to elastically bias rightward the lock plate 53. A cam member 59is formed in the front edge of the lock plate 53, and provided with aramp edge 57 which is formed in order to engage with theengagement/stopper portion 34 when the tuning shaft 14 retreats and totemporarily displace the lock plate 53 in the leftward direction in FIG.1 against the spring 56, and with an engagement/stopper step portion 58which is formed in the rear portion of the edge 57 and which engageswith and stops the engagement/stopper portion 34. In the lock plate 53,elongated holes 60 extending in the left-right direction are formed atpoints corresponding to the shafts 13 when the engagement/stopperportions 34 are engaged with first elongated guide slots 51 through theelongated holes 60.

The front portion of the bottom plate 31 of the support plate 15 isprovided with a change-over mechanism 61 for alternately preventing theleft and right tuning shafts 14 from. The change-over mechanism 61 isprovided with a longitudinal swing plate 62 and a pivotal plate 63 whichis disposed at the rear side of the swing plate 62. The swing plate 62is provided with a hole 64 at its middle portion, a pair of risingportions 65 and 66 opposite to and separated from each other at its rearportion, and a circularly-arced connecting hole 67 at its front portion.The rear portion of the pivotal plate 63 is disposed between the pair ofrising portions 65 and 66, and a pin 68 is secured in this rear portion.A hole 69 registered with the hole 64 and a pair of contact portions 71and 72 engaging with the portion 48 of the guide member 42 are formed inthe center of the front portion of the pivotal plate 63. A pivot axis 73is inserted into the holes 64 and 69 registered with each other and isfixedly attached at its lower end to the bottom plate 31 so that theswing plate 62 and the pivotal plate 63 are rotatably supported. The twoends of a snap spring 74 are respectively attached to the bottom plate31 and the pin 68 of the pivotal plate 63 so as to elastically bias thepivotal plate 63 in one direction. The swing plate 62 of the change-overmechanism 61 is disposed between a pair of left and right second guideslots 52 such that the front edge of the swing plate 62 closes eitherthe left-hand or right hand second guide slot 52 when the swing plate 62inclines either to the left or right. Further, a connecting pin 75 withits one end attached to the bottom plate 31 is fitted in the hole 67which is in opposition to the portion 48 of the guide member 42 attachedto the left and right tuning shafts 14 and in opposition to the contactportions 71 and 72 of the pivotal plate 63.

An upper plate 76 is provided on the respective upper ends of thefront-end rising portion 16 and the rear-end rising portion 17 of thesupport plate 15. A pair of first and second movable actuator plates 77and 78 are longitudinally provided on the back of the upper plate 76, asshown in FIG. 7. The first actuator plate 77 is disposed over the firstand the second tuning mechanisms 11 as seen from the left-hand in FIG. 1and the left-hand tuning shaft 14 of the central tuning mechanism. Thesecond actuator plate 78 is disposed over the rest of the tuningmechanisms 11 and the right-hand tuning shaft 14 of the central tuningmechanism 11. The bent portions 79 and 81 which are substantiallyperpendicularly bent downward are formed on each of the actuator plates77 and 78 at opposite ends in the direction of movement thereof. Thebent portions 79 of the respective actuator plate 77 and 78 areconnected with respective magnetic cores 85 and 85 of a first and asecond variable tuning element 82 and 83. Each of the bent portions 81is in contact with the tuning pieces 45 of the respective tuningmechanisms 11. On the opposite side portions of each of the first andsecond actuator plates 77 and 78, upwardly projecting pins 86 aresecured and separated from each other and aligned in the direction ofthe actuator plate. Elongated holes 87 extending in the direction ofmovement of the first and second actuator plates 77 and 78 are formed inthe upper plate 76 corresponding to the pins 86, and the pins 86 areloosely fitted into these elongated holes 87 so that the first andsecond actuator plate 77 and 78 can be moved in the rearward/frontwarddirection. At each of the longitudinally opposite ends of each of thefirst and second actuator plates 77 and 78, a spring 88 is attached atone end, the other end of the spring 88 being fixedly attached to theupper plate 76, so that the actuator plates 77 and 78 are alwayselastically biased frontwardly.

In FIG. 1, the tuning shaft 14 located at the right side of theoperation shaft 13 has moved rearwardly and the engagement/stopper 34 isengaging with the step portion 58 of the lock plate 53 so that theleft-hand tuning mechanism 11 is maintained in its retracted state. Theoperation shaft 13, the guide member 42 of the right-hand tuning shaft14 and the left-hand tuning shaft 14 are in their returned state. Assumethat, at that time, both the swing plate 62 and the pivotal plate 63 ofthe change-over mechanism 61 have been rotated in the counterclockwisedirection, as shown at (a) in FIG. 1. This state is shown in FIG. 8, andwhen the push-button 12 is turned in this state, the right-hand tuningshaft 14 rotates because the drive gear 28 meshes with the driven gear36. The turning of the tuning shaft 14 causes the tuning piece 45 tomove in the rearward/frontward direction on the tuning shaft 14. Theside surface of the tuning piece 45 is in contact with the vertical sidesurface of the guide member 42 so that the tuning piece 45 can movewithout turning. The top of the memory protrusion 44 of the tuning piece45 is in contact with the bent portion 81 of the actuator plate 78 sothat the actuator plate 78 moves against the elastic force of a spring88 according to the movement of the tuning piece 45. Consequently, thevariable tuning element 84 is varied so that a desired radio station canbe tuned in. After tuning, the selection of the desired radio station isfixed and memorized until the operation shaft 13 is rotated again.

Thus, after the desired radio station has been memorized in theright-hand tuning shaft 14 by means of the movement stroke of the tuningpiece 45, the push-button 12 is depressed. As described above, thechange-over mechanism 61 is in a state such that a part of the frontedge of the rotated swing plate 62 crosses the right-hand secondelongated guide slot 52. Therefore, the protrusion 49 of the guidemember 42 of the retracted right-hand tuning shaft 14 is prevented frommoving rearwardly by means of the front edge of the swing plate 62.Therefore, the pinion 25 is guided by the right-hand rack 47 and itmoves rearwardly while rotating. The guide member 42 of the left-handtuning shaft 14 with its rack 47 meshed with the pinion 25 movesrearwardly by an amount corresponding to the rotation of the pinion 25,and the pushing stroke of the operation shaft 13 is added thereto, sothat the guide member 42 moves rearwardly with the stroke which is twiceas large as the pushing stroke of the operation shaft 13. Theengagement/stopper portion 34 is made to be in contact with the bentportion 41 of the guide member 42 by means of the return spring 38 sothat the tuning shaft 14 moves rearwardly integrally with the guidemember 42. In that case, the engagement/stopper portion 34 cooperateswith the ramp edge 57 of the lock plate 53, and a transverse movementforce against the spring 56 is temporarily applied to the lock plate 53.Consequently, the engagement between the engagement/stopper portion 34of the right-hand tuning shaft 14 maintained at the rear and theengagement/stopper stepped portion 58 is released, so that theright-hand tuning shaft 14 is returned frontwardly by means of thereturn spring 38 independently of the guide member 42. On the otherhand, the bent portion 81 of the actuator plate 78 which retracts as theright-hand tuning shaft 14 returns comes in contact with the memoryprotrusion 44 of the left-hand tuning shaft 14 which has been retractedwith the operation shaft 13. Further, due to the engagement between theengagement/stopper portion 34 of the left-hand tuning shaft 14 and theengagement/stopper stepped portion 58 of the lock plate 53, theleft-hand tuning shaft 14 is maintained at the rear position, and atthis time the left-hand driven gear 36 meshes with the drive gear 28 asshown in FIG. 6.

When the depressing pressure on the push-button 12 is removed in thestate shown in FIG. 6, both the left-hand and right-hand guide members42 are retracted and the drive gear 28 and the driven gear 36 aremaintained in their meshed state. Next, the push-button 12 is turned inthis state, and the turning is transmitted to the left-hand tuning shaft14 so that the tuning shaft 14 is rotated. As described above, thedriven gear 36 has a diameter which is larger than that of the drivegear 28 so that the tuning shaft 14 can be finely rotated. The rotationof the tuning shaft 14 causes the tuning piece 45 to slide on the tuningshaft 14 so that the variable tuning element 84 is varied finely throughthe actuator plate 78 to thereby select another desired radio stationwhich is stored by means of the movement stroke of the tuning piece 45.

The operation of the change-over mechanism 61 will be described now.FIG. 1 shows, at (a) to (d), the operation steps of the change-overmechanism 61 which is changed over every cycle of reciprocation of theoperation shaft 13. In the state maintained by the snap switch 74 suchthat both the pivotal plate 63 and the swing plate 62 lean in thecounterclockwise direction as shown at (a) in FIG. 1, the portion 48provided on the left-hand guide member 42 strikes the contact portion 71of the pivotal plate 63 in its path. Therefore, as shown at (b) in FIG.1, the pivotal plate 63 moves clockwise and strikes at its leg endagainst the first rising portion 66, so that a clockwise pivotal forceis given to the swing plate 62. When the depressing pressure on thepush-button 12 is removed in this state so that the left-hand guidemember 42 is retracted together with the operation shaft 13 through theengagement of member 25, the protrusion 49 retracts while sliding alongthe side edge of the swing plate 62 as shown at (c) in FIG. 1. In thestate where the guide member 42 has been returned sufficiently, theswing plate 62 pivots in the clockwise direction so as to traverse theleft-hand second elongated guide slot 52, and this state is maintainedby the snap spring 74. Thus, the change-over mechanism 61 is reversiblychanged over alternately in the left and right directions at everyreciprocation of the operation shaft 13.

Thus, after desired radio stations have been respectively memorized inall the tuning shafts 14 provided on the support plate 15, if a desiredone of the push-buttons 12 is depressed and the operation shaft 13 ismoved rearwardly, one of the tuning shafts 14 which is able to retractis moved frontwardly at the same time. The radio station which has beenmemorized in the tuning piece 45 can be received through the variabletuning element by means of the contact between the memory protrusion 44of the tuning piece 45 of the tuning shaft 14 which has been moved andthe front bent portion 81 of the actuator plate 78.

Referring to FIGS. 8 to 13, a second embodiment of the present inventionwill be now described. In this embodiment, eight broadcasting stationsare selectively tuned in by four tuning mechanisms. An actuator plate isdivided into two actuator plates 91 and 92 each movably supported at itsopposite end portions extending parallelly with each other in thedirection of movement thereof by a pair of guide rods 94. That is, eachof the actuator plates 91 and 92 has at its rear end portion in thedirection of movement a rear-end rising portion 95 formed by upwardlybending the end portion by about 90 degrees, and has at its front endportion in the direction of movement a front-end rising portion 96 whichis similar to the rear-end rising portion 95 but is formed only at aportion below the guide rod 94. While not shown in the drawing, therising portions 95 and 96 respectively have through holes into which theguide rod 94 is inserted. Springs 97 are provided on the respectiveguide rods 94 at portions thereof between a rear-end rising portion 17of a support plate 15 and the respective rear-end rising portions 95 ofthe actuator plates 91 and 92 so as to always frontwardly bias theactuator plates 91 and 92.

The tuning mechanism in this embodiment will be described next. Achange-over lever 101 is pivotally mounted at its intermediate portionon a pin 24 of a support member 23. A pin 102 is mounted in thechange-over lever 101 at its rear end portion, and a spring 104 isprovided between the pin 102 and a pin 103 mounted in the support member23 at its front end portion for applying an elastic tensile force to thechange-over lever 101 such that when the rear end of the change-overlever 101 inclines somewhat leftward/rightward with respect to thedirection of movement of an operation shaft 13, it is caused to furtherincline in the same direction. The rear end of the change-over lever 101has a wide width such that a substantially V-shaped pair of tongueportions 105 and 106 are formed. A circularly arced slot 107 is formedin the wide width portion such that it extends across the tongueportions 105 and 106, and a pin 108 mounted in the upper surface of thesupport member 23 is received in this slot 107. Thus, the range ofpivotal movement of the change-over lever 101 is limited by thecooperation between the pin 108 and the slot 107. A front bent portion109 of the support member 23 is longer than the bent portion 21 of thepreviously described first embodiment and the end of this front bentportion 109 is receive a guide hole 111 formed in a bottom plate 31 ofthe support plate 15. This guide hole 111 extends in the direction ofmovement of the operation shaft 13 so as to guide the support member 23to slide in the frontward/rearward direction. An engagement/stopperportion 112 is formed at an upper end center of a rear bent portion 39of the guide member 42 of each tuning shaft 14 so as to cooperate withthe change-over shaft 14 to cause the tuning shaft 14 to moverearwardly. This engagement/stopper portion 112 engages with the frontedge of the tongue portion 105 or 106 of the change-over lever 101 so asto cause the tuning shaft 14 to advance in the same direction as theoperation shaft 13 when the operation shaft 13 is advanced to therearwardly-displaced position. A protrusion 113 is formed in the frontside-edge upper surface of the guide member 42. This protrusion 113engages with the rear edge of one of the tongue portions 105 and 106 ofthe change-over lever 101 to change the change-over lever 101 to theother.

A lower engagement/stopper portion 114 is formed in the lower-end centerof the front bent portion 39 of the guide member 42 and fitted into anengagement slot 115 formed in a lock plate 53. Similarly to the firstembodiment, the engagement slot 115 is formed with a ramp edge 57 and anengagement/stopper stepped portion 58.

When a push-button 12 is rearwardly and is in the state shown in FIG. 9,the rear edge of the left-hand tongue portion 105 of the change-overlever 101 strikes the engagement/stopper portion 112 of the guide member42 of the left-hand tuning shaft 14 to displace the tuning shaft 14rearwardly. The lower engagement/stopper portion 114 of the guide member42 moves rearwardly together with the tuning shaft 14 and engages withthe ramp edge 57 to cause the lock plate 53 to move left in FIG. 13.Thus, the engagement between the lower engagement/stopper portion 114 ofthe guide member of the right-side tuning shaft 14 and theengagement/stopper stepped portion 58 of the engagement slot 115 isreleased so that the right-hand tuning shaft 14 is caused to come backfrontwardly by a spring 38. The lower engagement/stopper portion 114 ofthe guide member 42 of the left-hand tuning shaft 14 reaches theengagement/stopper stepped portion 58 from the ramp edge 57 and islocked by this engagement/stopper stepped portion 58. If the push-button12 is released in this state, the operation shaft 13 is caused to returnby the spring 29. In this returning operation, the front edge of thetongue portion 105 of the change-over lever 101 strikes against theprotrusion 113 of the left-hand tuning shaft 14 to cause the change-overlever 101 to rotate clockwise. At this time, if the line connecting thepins 24 and 102 of the change-over lever 101 inclines to the right evena slight amount, the change-over lever is caused by the spring 104 torotate to the right to the extent allowed by the slot 107 and the pin108. Thus, the change-over lever 101 is alternately swung clockwise andcounterclockwise by the striking action of every reciprocation of theoperation shaft 13.

Although the push-button tuner is arranged by a tuning mechanism inwhich two broadcasting stations are selectively tuned in by eachpush-button in the second embodiment, it is a matter of course that thepush-button tuner may be arranged by a tuning mechanism in which onlyone broadcasting station is tuned by each push-button. In the lattercase, it is sufficient to make the change-over lever 101 fixedly incontact with the engagement/stopper portion 112 of each tuning shaft 14.Accordingly, not only the spring 104 and the pins 24 and 102 at theopposite ends of the spring 104, but the slot 107 and the pin 108 becomeunnecessary.

What is claimed is:
 1. A push-button tuner comprising a support, atuning means mounted on said support in a manner so that said tuningmeans is movable to positions corresponding to tuned frequencies forproducing the tuned frequencies, and a plurality of presettable tuningmechanisms for adjusting said tuning means to move selectively topositions respectively corresponding to specific frequencies, in whicheach of said tuning mechanisms comprises:a rotatable operation membermovable between a front non-actuation position and a rear actuationposition, said operation member being normally urged to said frontnon-actuation position, said operation member having a drive rotary bodyand a push-button provided at an end of said operation member, saidpush-button being used also as a rotating knob; a rotatable tuningmember having a driven rotary body for selectively engaging with saiddrive rotary body to rotate together with said drive rotary body, saidrotatable tuning member being supported by said support in a manner sothat said rotatable tuning member is normally urged to said frontnon-actuation position while it is movable between said frontnon-actuation position and said rear actuation position, said rotatabletuning member having a longitudinally extending threaded portion at apart of the surface thereof and a tuning piece engaged with saidthreaded portion, said tuning piece being movable in thefrontward/rearward direction in response to the rotation of said tuningmember; said tuning means including a plurality of actuator platesengaging with said tuning piece of said tuning member in said rearactuation position to adjust said tuning means, each of said actuatorplates cooperating with preset number of said tuning mechanisms, each ofsaid actuator plates being provided with a variable tuning element; andin which said push-button tuner further comprises a lock member forholding any one of said tuning members so as to permit the transmissionof rotation between said drive rotary body and said driven rotary bodywhen said one tuning member is located in said rear actuation positionand for releasing said one tuning member held in said rear actuationposition when another tuning member is disposed in said rear actuationposition.
 2. A push-button tuner according to claim 1, in which saidplurality of actuator plates are frontward/rearward movably supported byan upper plate member provided on said support in a manner so as tocover said plurality of tuning mechanisms.
 3. A push-button tuneraccording to claim 1, in which said plurality of actuator plates arefrontward/rearward movably supported by a guide rod member supported atits opposite ends by said support at the front and rear ends thereof. 4.A push-button tuner according to claim 1, in which said driven rotarybody has a diameter larger than that of said drive rotary body.
 5. Apush-button tuner according to claim 1, in which said drive rotary bodyis mounted on said operation member slidably in the axial direction ofsaid operation member, said operation member including means for urgingsaid drive rotary body to said front non-actuation position and arestriction member for restricting the position of said drive rotarybody in a manner so that rotation is allowed to be transmitted from saiddrive rotary body to said driven rotary body when said tuning member isheld in said rear actuation position.
 6. A push-button tuner accordingto claim 1, in which said actuator plates are separately disposed at apredetermined distance on said tuning member and supported by saidsupport slidably in the same direction as the direction of movement ofsaid tuning piece.
 7. A push-button tuner according to claim 1, in whicha pair of said tuning members are provided at the opposite sides of saidoperation member, and in which each of said tuning mechanisms includesan engagement mechanism supported by said operation member and engagingwith said pair of tuning members in a manner so as to alternatelydisplace said pair of tuning members relative to said operation memberin the direction toward said rear actuation position.
 8. A push-buttontuner according to claim 7, further comprising an enlargement mechanismfor transmitting an enlarged amount of displacement of said operationmember in the direction toward said rear actuation position to saidtuning member movable to said rear actuation position.
 9. A push-buttontuner according to claim 8, in which said enlargement mechanism includesa support member movable in response to the frontward/rearward movementof said operation member, a pinion horizontally rotatably mounted onsaid support member, and a guide member movable in response to thefrontward/rearward movement of said operation member and having a rackengaging with said pinion.